Fosi AudioSK01 Headphone Amplifier Equalizer Preamp with Bass Midrange Treble Tone Control and Loudness Compensation Portable Class A Analog Amp with 3.5mm 6.35mm Jacks

Fosi SK01 delivers on many fronts, with its versatility. The sound quality is very smooth too.I've used it with my bass heavy Soundcore boom plus 2 Bluetooth speaker, it literally tames the bass, and the ability to also increase/decrease midrange and treble frequencies too makes the speaker sound stupendously awesome, and a joy to listen too !Results are also very good on my mobile phone, TV and DJ controller.Not so good on my laptop, but that's purely because the laptop manufacturer has skimped on quality audio components, having said that it still sounds great, but with less oomph.All the knobs, buttons and inputs/outputs just work like they should, and my Sennheiser headphones have come alive too.No need to have the volume up too loud either as it delivers great audio quality.Battery life is dependent on how hard you use it, but satisfying all the same.The warning indicator light above the treble knob will flash when the battery power is running low, and show red when you're charging it up.When fully charged, the red light will go out.You can continue to use it when it's charging, but I think it's best to make it charge undisturbed, to prolong the overall longevity of the battery life.The light below the volume knob will flash faster when the volume is too loud, another nice touchMy lower quality music files are also enhanced by the Fosi SK01, as I take advantage of the ample frequency ranges provided to tailor and boost the sound where ever it is needed.The sleek rectangular shape is aesthetically pleasing to look at and solidly built, the bottom of the knobs are almost seamless against the main body of the amp, which eliminates dust getting insideI'm not a headphone amp connoisseur so can't compare, and no doubt there are brilliant premium models out there, costing mega bucks !But Fosi Audio have come up with a winner, that covers many bases, delivering real quality at a price point that doesn't break the bank.One more point…I wish it had Bluetooth capability, to combine with my Bluetooth speaker, to eliminate using leads connecting them together, when I'm out in the public domain.Overall, though, a very well-thought-out product that deserves the accolades and positivity lavished upon it.Well doneFosi Audio 💯 🔥🔥🔥🔥🔥🔥😁

I like this device, my only criticism is that because there is a rechargeable battery on board the device needs to be switched off when not in use. I would prefer the on/off switch to be separated from the volume control. Turning this thing on and off every day will probably lead to unnecessary and premature wear of the volume control resistive track. That aside, the first thing I noticed, was how well the item is made. It is beautifully engineered and the feel of the controls inspire confidence. The range of the tone controls from plus to minus allows the user to adjust the sound just as you would wish. I am impressed by the dynamic range of the amplifier. I have fitted this FOSI audio SK01 to my active speakers because they don't have tone controls and the result has transformed my listening experience. I am planning to buy another SK01 to be used as an interface between my mp3 player and headphones.

I bought this after being underwhelmed by my active speakers when using the sound output from my monitor. Music played sounded flat & tinny on my desk. I knew my speakers were capable of far more so I decided to take a chance on this product despite it costing more than my speakers, mainly due to all of the positive reviews. It was worth every penny. My speakers finally sound as good as they should. The bass has a lot more punch, and I love the control over the mid & high range frequencies. The product is small and compact enough to have it hidden under my monitor stand. I would definitely recommend the the SK01.

This is a good little amp with an audio input and EQ control, it’s got some good power and the EQ is nice but still requires a DAC or something to function. The small form factor is nice and fits easily on a desk, the unit is not too heavy and you will need to hold it when plugging in headphones to stop it from moving.

got this to power my Fiio ft5 I got this mainly so I can dial back some of the bass, there seems to be a fair bit of power behind it and it really helps pick up some of the quieter details and ambience in-game witch is what am after, as it has bass, treble and mid-range dials so you can adjust to taste or if your switching from music to gaming to can dail in the sound you want, over all very happy with amp 10/10

Don't often give glowing reviews but it is a pleasure to recommend this little gem. It does everything you would wish for a headphone amplifier. Volume excellent (I am quite deaf), tone control excellent, loudness effective as are treble, middle and bass.What more can I say ?Oh yes ! Price very reasonable. And I don't need my hearing aids.

I bought this to adjust the gain and EQ of the audio out from my iPad. The Apple iOS only allows you to EQ the sound, presets only, when using their own music player, but I use a 3rd party app to play my backing tracks when working as a singer/guitarist, so I needed something external. The first thing I noticed was the solid look and feel of the product, a pleasing satin finish to the metal casing and a reassuring weight, the controls knobs having a nice firm feel to them. The Bass, Middle and Treble controls have a pleasing mid-position, flat response detent. With 3 band EQ options, loudness and gain level switching, this product fits the bill perfectly. It has an internal rechargeable battery, charged via the supplied USB C cable. I fully charged the unit, removed the charging cable, set it up to play a radio into headphones and then went out and left it. Seven hours later it was still playing!

First it's a really well-made unit very solid the controls are really nice, there is a reasonable amount of boost certainly for any 34 ohm phones. The downside on my setup (pc —USB DAC — fosi headphone amp — pass-through to small bookshelf speakers) was background noise especially on the pass-through if I unplugged the speakers and set them up via a Y cable before the fosi amp it was a lot better, it's possible with a better/different set up the noise wouldn't have been a problem.